You are saying that the President has immense power that is unchecked by the Congress but then are also complaining about Congress impeding the President. Which one is it because you can't have it both ways?
Executive orders are subject to judicial review, and the Republicans have had a majority in the Senate for the past 4 years, which they still have. No president can create sweeping changes to the culture of the nation without the support of both the Congress and the judicial branch.
The US Constitution is a pretty flawed document (albeit one with good intentions). That's why we've had to amend it so many times. I didn't say that America is evil because white men designed it (and I doubt that anyone else has actually said that either), but I did say that rich white men designed it to protect their own interests - as the facts bear out. Non-land-owning white men couldn't vote in all states until 1856. How do you reconcile that with "all men are created equal" verbiage?
I used to work for the US Supreme Court and until the first activist justices came from the Bush administration. And yet, Scalia and Ruth Bader Ginsburg were such good friends and had so much respect for each other that their families used to spend New Year's Eve together. Retired Justice John Paul Stevens, a Republican, objected to Kavanaugh being elevated to the Court in large part because he was so clearly political and so clearly not of the temperment to set that aside for the good of the nation. The Republicans refused to confirm Merrick Garland, someone they had been suggesting as a good candidate for the USSC for years until Obama officially nominated him, and then all bets were off. The politicization of the court is squarely on the shoulders of the Republicans, although I agree that it is a shame.
As I've already indicated (with citations), there is overwhelming bipartisan public support for gun reform and it is only Congress who is keeping the will of the people from being enacted. Harris saying that she will attempt to redress that doesn't mean that she would actually be able to do so. It just means that she would attempt it. And she said that when she was running for President. There's no guarantee she will ever hold that position. Why is it that things that Trump has said that are potentially inflammatory are political rhetoric said to appeal to his supporters and don't necessarily reflect his views, but if a Democrat does the same thing, she's a menace?
You know that I'm an Independent and not a particular fan of either Biden or Harris, so I hope you will take my remarks as my opinion that is separate from political allegiance.